Fourteen quarterbacks were called during the three-day NFL Draft marathon, and at least half will be busts in the long run. Expect none to make a bigger impact this season than Josh McCown will for the Tampa Bay Buccaneers.

McCown was a third-round pick in 2002, and 12 years later, the Buccaneers are building an offense around the journeyman.

It takes a few years to accurately judge a draft class for most teams, so issuing grades today is a pointless exercise. The success of a marriage is not determined after the honeymoon.

But for football handicappers, there is a point to analyzing the draft and projecting the future. The lines for Week 1 of the regular season are up, and no rookies are going to change the numbers now by a point.

Still, in this draft, there were teams that got significantly better and there were players picked who will make immediate impacts. Tampa Bay, in the middle of a positive offseason, got better over the weekend.

“The Buccaneers had already upgraded their entire team,” LVH sports book director Jay Kornegay said. “McCown is certainly an upgrade. That’s the offseason sharp-guy team right now. That’s definitely a team that will be bumped up in the power ratings.”

For a seven-week stretch last season, McCown posted the highest passer rating of any quarterback in the league. He thrived by throwing the ball up to the Chicago Bears’ big targets, Brandon Marshall and Alshon Jeffery. But the Bears let McCown walk in free agency, and the Buccaneers were sharp to pick him up.

Tampa Bay took another smart step by drafting two big weapons for McCown. Mike Evans, a 6-foot-5-inch wide receiver from Texas A&M, was the seventh pick of the first round. The Bucs grabbed Austin Seferian-Jenkins, a 6-5, 260-pound tight end from Washington, in the second round. Evans and Seferian-Jenkins complement the team’s primary receiver, 6-5 veteran Vincent Jackson.

New coach Lovie Smith has upgraded the defense, so he used all six draft picks on offensive players to help McCown, who is set to put up the type of impressive numbers he did with the Bears.

I recently recommended betting the Buccaneers over their win total of 6½ — a number posted at the South Point — and their draft haul has reinforced that opinion.

For the most part, the draft is a dog and pony show, and the grading process is best left to ESPN genius Mel Kiper Jr., who spends his days in a dark film room styling his hair and studying the techniques of interior linemen.

Kiper graded the Indianapolis Colts’ draft as the worst, and he has a point. The Colts had no first-round pick and only five total, and they failed to pick up an obvious impact player.

But here were the best impact-player picks from the draft, guys who should factor into your handicapping in the future:

■ It might have been a reach for Jacksonville to take Blake Bortles at No. 3, but the Jaguars needed a quarterback, and the former Central Florida star could be a good one. He’s likely to be a backup this season. Jacksonville found some value with wideouts Marqise Lee and Allen Robinson in the second round.

■ Oakland’s top two picks get high marks. Khalil Mack, a linebacker from Buffalo, was a low-risk pick at No. 5. The Raiders might have found their quarterback of the future, Derek Carr from Fresno State, in the second round. Carr is probably a year away, but he eventually should be a quality starter.

■ Philadelphia coach Chip Kelly overcame the loss of DeSean Jackson by adding two big-play receivers, Vanderbilt’s Jordan Matthews and Oregon’s Josh Huff. The Eagles’ offense still will be explosive.

■ San Francisco used its 12 picks wisely. Carlos Hyde, a second-round running back from Ohio State, and Chris Borland, a third-round linebacker from Wisconsin, are physical players who fit the 49ers and will help right away.

■ Defense was a need Green Bay addressed. But the Packers also picked a pair of receivers, Davante Adams from Fresno State and Jared Abbrederis from Wisconsin, to assist Aaron Rodgers.

■ Sammy Watkins makes Buffalo a much more dangerous offensive team. Maybe the Bills traded too much to get the Clemson receiver at No. 4, but he should make the biggest impact of any rookie.

■ There was euphoria in Cleveland over getting Texas A&M quarterback Johnny Manziel at No. 22. The hangover hit the next day when it was reported top receiver Josh Gordon could be suspended for the season. The Browns had a good draft, but did not snag a receiver, and Gordon’s loss would be a setback for Johnny Football.

Dallas, Houston, Pittsburgh and St. Louis also made significant improvement in the draft.

All of those teams get high grades, along with Tampa Bay, for what it’s worth to power ratings in May.